1. Field of the Invention
The invention relates to a leakage detection apparatus and method, and in particular, the invention relates to a leakage detection apparatus and method for a multi-channel inkjet cartridge.
2. Description of the Related Art
Advances in industries employing chemical and biological processes have created a need for devices that accurately and automatically dispense small quantities of liquids containing chemically or biologically active substances for commercial or experimental use. Accuracy and precision in the amount of liquid dispensed is important both from the standpoint of causing a desired reaction and minimizing the amount of material used. An example of a device with an array of reagents disposed thereupon is a biochip.
Many conventional dispensing methods that can cause a desired reaction and minimize the amount of material are disclosed, for example, in U.S. Pat. No. 5,551,487, U.S. Pat. No. 5,807,522, U.S. Pat. No. 6,110,426, WO 02/16021, and U.S. Pat. No. 6,458,583. From the standpoint of reliability, it is important to prevent different reagents from intermixing during dispensing, thus affecting detection results.
In view of this, a multi-channel inkjet cartridge with replaceable capillary tubes is disclosed, thus preventing intermixing of different reagents. As shown in FIG. 1, the multi-channel inkjet cartridge 10 includes a base 11, a chip 12, a nozzle plate 13, and a plurality of capillary tubes 14. It is noted that the nozzle plate 13 adheres to the chip 12 via a barrier layer (not shown). The chip 12 also adheres to the base 11, and the capillary tubes 14 which are disposed in the base 11 in a replaceable manner. It is understood that the leakage between different reagents may occur between the base and the chip, between the chip and the barrier layer, or between the barrier layer and the nozzle plate. However, there is no leakage detection apparatus and method for a multi-channel inkjet cartridge.
U.S. Pat. No. 6,431,678 discloses an ink leakage detection apparatus. Referring to FIGS. 2a–2b, detectors 21 are formed around contact pads 22 such that the leakage of ink onto both the detector 21 and power and control lines 23 causes a voltage to be propagated through the conductive ink to the detector 21. The detector 21 is in turn coupled to the detection circuit which outputs an ink leakage signal upon receipt of a voltage from a power or a control line 24 or other source. Thus, leakage detection can be performed. It is understood that the inkjet print head 20 includes a chip 25, a barrier layer 26, and a nozzle plate 27.
Although the apparatus disclosed in U.S. Pat. No. 6,431,678 can detect leakage in some inkjet print heads, it is not applicable to a multi-channel inkjet cartridge as shown in FIG. 1. Specifically, the detection apparatus shown in FIGS. 2a–2b cannot determine which channel is leaking. Additionally, it cannot detect leakage between the base 11 and the chip 12 as shown in FIG. 1.